Retell AI

What it's good for

• 1

  Inbound phone agents that answer, qualify, and route callers

• 2

  Outbound lead-generation and follow-up calls at scale

• 3

  Appointment scheduling and reminder calls

• 4

  Overflow and after-hours coverage so calls never go unanswered

• 5

  Front-line support that resolves common questions before escalating to a person

Pricing

• Voice engine

  Before model and telephony

  $0.07/min

• All-in typical

  Roughly $0.13 to $0.31/min all-in

  $0.13/min

• Concurrency

  20 concurrent calls free, extra lines $8 each

  $8/line/mo

• Enterprise

  Volume pricing as low as $0.05/min

  $0.05/min

How to use it

Build an agent in Retell's dashboard by setting its prompt, voice, and the LLM behind it, then test the conversation flow before it goes live. Attach a phone number for inbound or outbound calling and add function calls so the agent can look up data or hand off to a human. Watch latency and transcripts during testing and tune until it sounds natural. With 20 free concurrent calls, you can handle real volume before paying for extra lines, and at scale the Enterprise rate down to $0.05/min changes the math on high-call-volume campaigns.

Pros & cons

Frequently asked questions

• How much does Retell AI cost?

  The voice engine is $0.07/min, but the realistic all-in cost is about $0.13 to $0.31 per minute once you add the LLM and telephony. Twenty concurrent calls are free, extra lines are $8 each per month, and Enterprise volume pricing can drop as low as $0.05/min. There is no flat subscription; you pay for call time.

• Retell AI vs Vapi: which should I choose?

  They are the two leading phone-agent platforms and are very close. Retell AI has a slightly higher headline voice-engine rate ($0.07/min vs Vapi's $0.05/min platform fee) but doubles the free concurrency to 20 calls and charges $8 per extra line versus Vapi's $10. Vapi leans more developer-first and model-agnostic. Compare them on the real all-in per-minute cost and how many concurrent lines you need.

• Is Retell AI free?

  The platform is paid and usage-based, so live calls are billed at roughly $0.13 to $0.31 per minute all-in. What is free is concurrency: 20 simultaneous calls are included at no extra charge, which lets you handle meaningful volume before buying more lines. But the call minutes themselves are not free.

• What is Retell AI best for?

  Deploying phone voice agents for inbound handling, outbound lead generation, scheduling, and after-hours coverage. The 20 free concurrent calls and low Enterprise per-minute rate make it a strong fit for higher-volume calling campaigns.

• How many calls can Retell AI handle at once?

  Twenty concurrent calls come free, and you add capacity by buying more lines at $8 each per month. That higher free allowance is one of its main differences from Vapi, which includes ten. For very high volume, Enterprise plans scale concurrency with better per-minute rates.

More

• Retell AI docs
• Retell AI pricing

Alternatives to Retell AI

Other tools we'd consider for the same job.

• Vapi

  Developer-first platform for building voice AI agents that make and take phone calls. Usage-based, per-minute pricing

• Lindy

  No-code agent builder with 1,600+ integrations. The pragmatic answer when LangGraph is overkill but Zapier can't express the logic

Other Agents tools

• Vapi

  Developer-first platform for building voice AI agents that make and take phone calls. Usage-based, per-minute pricing

• Dify

  Source-available, self-hostable platform for LLM apps and agents. Visual workflows, RAG, and agents in one package

• n8n

  Open-source workflow automation with first-class LLM + vector-DB nodes. Self-host or use their cloud

• LangGraph

  Code-level framework for building multi-step, stateful LLM agents. The serious engineer's choice for agent orchestration